Synthesis of cyano(selenone)gold(I) complexes and investigation of their scrambling reactions using 13C and 15N NMR spectroscopy

Abstract

A number of new cyano(selenone)gold(I) complexes have been prepared and characterized by elemental analysis, IR and NMR methods for a series of selenones (imidazolidine-2-selenone and its derivatives or diazinane-2-selenone). It appears from the IR data two of the seven prepared complexes exist as nonionic complexes, [CSeAuCN] while the remaining five exist as the ionic species, [Au(CSe) 2] +[Au(CN) 2] − in the solid state. In solution, all complexes are observed to undergo ligand scrambling reactions exhibiting the equilibrium, 2 [CSeAuCN]⇆[(CSe) 2Au] ++ [Au(CN) 2] −. Ligand scrambling reactions of the complexes have been studied in DMSO using 13C and 15N NMR spectroscopy. As a result of the scrambling reaction two sharp resonances are observed in all complexes for both the carbon and nitrogen of CN − in 13C and 15N NMR, respectively, corresponding to the two equilibrium components, [CSeAuCN] and [Au(CN) 2] −. Equilibrium constants ( K eq) were determined for the scrambling equilibria by integrating the CN − resonances in the 13C NMR, recorded at 297 K. K eq values obtained for cyano(selenone)gold(I) complexes are the highest of all the reported values, measured for other complexes.